The only strategy I can suggest is to play the game using your own imagination for a few hours until you get bored, then use the element guide in The Evil Genius to find the missing elements you still need.

Doodle Devil requires you to combine different elements, in order to unlock other elements with which to combine your original elements, in order to.....you get the idea. In order to complete this game you need to unlock all 190 elements, some of which will be provided for you to act as a base for your own combinations.

All the trophies available in this game are achievable in one playthrough.

Combo!Create two new elements in a row.

Devil's DozenCreate 13 different elements.

Unmissable

Note that the requirement for unlocking this trophy is to create thirteen different elements, not unlock thirteen different elements. I point this out because at the start of episode two you will have a lot of new elements (15 in total) but you will not achieve the trophy until you have created thirteen elements of your own.

Accidental Well-doerComplete the Good group.

Unmissable

In order to gain this trophy you simply need to discover all the elements that make up the Good group. Check the spoiler below for the complete list of elements, or check The Evil Genius for the complete list of element combinations.

Toggle Spoiler

Good Group

Prayer

Angel

Religion

Friendship

Heavens

Life

Resurrection

Light

Soul

Order

VivisectorComplete the Monsters group.

Unmissable

In order to earn this trophy you simply need to discover all the elements that make up the Monsters group. Check the spoiler below for the complete list of elements, or check The Evil Genius for the complete list of element combinations.

Toggle Spoiler

Monsters Group

Cerberus

Mutant

Cthulhu

Vampire

Demon

Frankenstien

Ghost

Werewolf

Ghoul

Zombie

Walking in God's ShoesComplete the Nature, Animals, and Plants groups.

Unmissable

In order to gain this trophy you simply need to discover all the elements that make up the Nature, Animal and Plant groups. Check the spoiler below for the complete list of elements, or check The Evil Genius for the complete list of element combinations.

Toggle Spoiler

Nature Group

Animal Group

Plant Group

Metal

Beast

Apple

Air

Rat

Seeds

Steam

Bat

Bacteria

Ash

Snake

Spore

Earth

Pigeon

Coffee

Energy

Egg

Grass

Stone

Wolf

Mushroom

Fire

Fish

Tobacco

Water

Worm

Razorvine

Lava

Piranha

Tree

Science!Complete the Science group.

Unmissable

In order to unlock this trophy you simply need to discover all the elements that make up the Science group. Check the spoiler below for the complete list of elements, or check The Evil Genius for the complete list of element combinations.

Toggle Spoiler

Science Group

Alien

Satellite

Cellulose

UFO

Laser

Plasma

Radiation

Virus

Rocket

Void

Sweet Little ToysComplete the Weapons and Military groups.

Unmissable

In order to gain this trophy you simply need to discover all the elements that make up the Weapons and Military groups. Check the spoiler below for the complete list of elements, or check The Evil Genius for the complete list of element combinations.

Toggle Spoiler

Weapons

Military

Gun Powder

Napalm

AK-47

Radar

Hand Grenade

Landmine

Armour

Airplane

Bazooka

Bomber

Desert Eagle

Cannon

Missile

Battlecruiser

Firearm

Helicopter

Warrior

Submarine

Flame-thrower

Tank

Space SuperstarComplete the Space War group.

Unmissable

In order to gain this trophy you simply need to discover all the elements that make up the Space War group. Check the spoiler below for the complete list of elements, or check The Evil Genius for the complete list of element combinations.

Toggle Spoiler

Space War

BFG 9000

Plasma Gun

Death Ray Gun

Space Marine

Death Star

Disintegrator

Force Field

Spaceship

Light Saber

Vacuum Bomb

Great DistortionComplete second episode without using tips.

Missable

On the main game screen you have five symbols down the left hand side, two of which show light bulbs. The light bulb symbols give you clues to which elements to combine. Complete episode two without touching these symbols if you wish to earn this trophy.

Toggle Spoiler

Episode two ends with the discovery of War

Lord of WarComplete third episode without using any tips.

Missable

On the main game screen you have five symbols down the left hand side, two of which show lightbulbs. The lightbulb symbols give you clues to which elements to combine. Complete episode three without touching these symbols if you wish to unlock this trophy. Note that this trophy will unlock at the same time as The Evil Geniuswhen you finish the game.

Unholy ChainCreate 50 elements in a row.

Missable

In order to achieve this trophy, you need to complete a total of 50 different element combinations without any failures.
If you are struggling with this one then see the The Evil Geniustrophy below for the complete list of all 190 elements found in Doodle Devil.

The Evil GeniusComplete the game without using tips.

Missable

On the main game screen you have five symbols down the left hand side, two of which show light bulbs. The light bulb symbols give you clues to which elements to combine. Unlock all 190 elements in Doodle Devil without using these symbols in order to earn this trophy.

For the full list of 190 elements and the combinations required to unlock them, check the spoiler below.